The subject matter disclosed herein relates to the art of steam turbomachines and, more particularly, to an asymmetric butterfly plate for a steam turbomachine exhaust hood.
Many power generation facilities employ steam turbomachine systems having a low pressure (LP) steam turbine portion coupled to an intermediate pressure (IP) steam turbine portion and a high pressure (HP) steam turbine portion to drive a generator. In general, steam is expanded in the LP steam turbine portion and channeled into an exhaust hood. The exhaust hood separates steam from atmospheric conditions, while providing support to rotating and stationary turbomachinery. Generally, stationary components direct steam toward rotating components to facilitate rotor rotation that is employed in power generation.
An exemplary exhaust hood is formed from various complex sheet metal plates that are combined to form a shell assembly. The shell assembly is formed to include various connections for internal and external components. The shell assembly includes upper and lower halves that guide steam downward toward a condenser. The exhaust hood includes a butterfly plate that turns an upper steam flow 180° downward toward the condenser. Existing butterfly plates include both linear and elliptical cross-sectional profiles that turn the upper steam flow vertically downward.